female doggy intercourse!

Question
I have 2 male shihtzu's breeding a female. How much is too much for her? Should i separate them?

Answer
You have 2 males breeding one female?

All kinds of red flags arise for me including the real chance that an infection can be spread to all three, you don't know which pup will inherit which trait, who's the sire and so on.

Regardless, a female needs only to be breed once a day over the course of her season (between about day 9 to 15).  You can also skip a day in between breedings.  Any more is overkill as the number of eggs your female releases determines the number of pups.

Good luck